1. Field of the Invention
The present invention relates to a three-dimensional imaging system, and in particular, it relates to improvements in three-dimensional image display technology for presenting so-called three-dimensional images to a plurality of people.
2. Description of the Related Art
Image display devices, which display images over a plurality of image display screens, have been developed. For example, in Japanese Laid-Open Patent Application 60-89209, and Japanese Laid-Open Patent Application 60-154287, and the like, image display devices capable of displaying common images simultaneously on a plurality of image display screens (multi-screen), are disclosed. In these image display devices, a large memory space is divided up by the number of screens, and the image in each divided memory area is displayed on the corresponding screen.
Furthermore, with the progress in recent years of display technology based on virtual reality (VR), three-dimensional display devices for presenting observers with a sensation of virtual reality over a plurality of image display screens, have appeared. A representative example of this is the CAVE (Cave Automatic Virtual Environment) developed in 1992 at the Electronic Vizualization Laboratory at the University of Illinois, in Chicago, U.S.A. Using a projector, the CAVE produces three-dimensional images inside a space by displaying two-dimensional images on display screens located respectively in front of the observers, on the left- and right-hand walls, and on the floor, to a size of approximately 3 m square. An observer entering the CAVE theatre is provided with goggles operated by liquid crystal shutters. To create a three-dimensional image, an image for the right eye and an image for the left eye are displayed alternately at each vertical synchronization cycle. If the timing of the opening and closing of the liquid crystal shutters in the goggles worn by the observer is synchronized with the switching timing of this three-dimensional image, then the right eye will be supplied only with the image for the right eye, and the left eye will be supplied only with the image for the left eye, and therefore, the observer will be able to gain a three-dimensional sensation when viewing the image.
In order to generate a three-dimensional image, a particular observer viewpoint must be specified. In the CAVE, one of the observers is provided with goggles carrying a sensor for detecting the location of the observer's viewpoint. Based on viewpoint coordinates obtained via this sensor, a computer applies a matrix calculation to original image data, and generates a three-dimensional image which is displayed on each of the wall surfaces, and the like.
The CAVE theatre was disclosed at the 1992 ACM SIGGRAPH conference, and a summary has also been presented on the Internet. Furthermore, detailed technological summaries of the CAVE have been printed in a paper in "COMPUTER GRAPHICS Proceedings, Annual Conference Series, 1993", entitled "Surround-Screen Projection-Based Virtual Reality: The Design and Implementation of the CAVE" (Carolina Cruz-Neira and two others).